C The objectives of this proposed research are to: Determine the effects of palatopharyngeal incompetency on lingual articulation. Determine the effects of open-bite malocclusion on lingual articulation. Determine the effects of Class III malocclusion on oral port constriction, lingual position and sound intelligibility. Quantify patterns of palatolingual constrictions and lingual impedance to airflow in normal, cleft palate, and speakers with anterior malocclusions as they relate to specific speech sounds. Develop a system for acquiring, processing and displaying data acquired simultaneously from aerodynamic, palatographic, kinesiologic and acoustic instruments. Develop a theoretical model for fricative production in normal and disordered speech due to cleft palate and/or malocclusion. Test this theoretical model against normal and disordered speakers. The methods utilized to study these relationships between cleft palate, malocclusion, lingual articulation and speech performance will include: pressure flow technique, acoustic analysis, dynamic palatography, magnetometry, and subjective speech judgements.